Slide-rule pencil



Dec. 17, 1946. R. c. MAGEE SLIDE-RULE PENCIL Filed March 9, 1945 cauti C. 4:42.70., JNVENTOR.

Patented Dec. 17, 1946 UNITED STATES PATENT GFFICE SLIDE-RULE PENCIL Robert C. Magee, Dayton, Ohio Application March 9, 1945, Serial No. 581,886

5 Claims. 1

My invention relates to devices which are usable both as a pencil and as a slide-rule and which may be conveniently carried around in the pocket, the same as a pencil or fountain pen; and its object is to provide Certain improvements therein and more particularly to provide means whereby the movable parts of such a device may be easily and quickly locked together so as to be held against relative movement when the device is used as a pencil.

In the drawing,

Fig. l is a view in side elevation of a deviceembodying my invention;

Fig. 2 is a view thereof in longitudinal section on a larger scale; and

Fig. 3 is a view in transverse section taken on a plane indicated by the line 3-3 in Fig. 2.

The pencil il! may be of any type or indeed any writing implement whatever; as shown herein, it is a lead rellable pencil having a magazine I i for the storage of new leads, which magazine is closed by a stopper I2 on the end of which an eraser I3 may be provided. The pencil, as shown, is also preferably provided with a raised portion I4 (Fig. 3) on its periphery for a purpose presently to be referred to. Closely tted around the pencil and movable longitudinally therewith is a tubulal` member or slide I5 which may, if desired, extend practically the entire length of the pencil and which has a longitudinal slot I6 through which the surface of the pencil is visible. The visible portion of the pencil is marked lengthwise with a Scale (as indicated in Fig. l) suitably graduated to serve as one of the scales of a slide-rule. There may also be marked i on the tubular slide along one or both of the edges of the longitudinal slot IS thereof, graduations appropriate for use as scales of a sliderule in cooperation with the scale marked on the pencil. The raised portion I it of the pencil projects into the slot IS and its purpose is to prevent relative rotary movement between the tubular slide and the pencil so as to keep the scale on the pencil in register at al1 times with said slot. Said raised portion may have, and preferably has, the form of a longitudinal ridge extending the full length of the pencil and exactly tting said slot; and in such case the scale carried by the pencil is marked upon this ridge.

Movably embracing the tubular slide l is a i cursor having a transparent portion il marked with an index-line or lines it and through which the respective scales of the tubular slide and pencil are visible. Said cursor is provided with means to lock it and the pencil and tubular-slide immovably together so that when the device is used as a pencil there can be no relative movement between these parts. Such locking means may comprise a spring nger I9 of which one end is secured to the cursor and the other end carries a locking lug or pin 2li. The tubular slide I5 is provided at its upper end with an annular shoulder 2i which limits the movement of the cursor toward that end, as shown in Fig. 2, and, near said shoulder, with a hole 22 which, when the cursor is in the position shown in that figure, registers with said locking lug or pin; and the pencil has a recess 23 with which the hole 22 also registers when the parts are in the position shown in Fig. 2. Through means, such as a thumb-slide 24, movable upon the cursor and having a projection 25 which rides along the spring finger I9 when the thumb-slide is moved forward, said locking lug or pin may be caused, when the parts are in the position shown in Fig. 2, to pass through the hole 22 in the tubularslide I5 and into the recess 23 of the pencil, thus locking the curso-1', tubular slide and pencil immovably together; and when the thumb-slide is retracted to its rearward position, that is the position shown in Fig. 2, the spring linger I9 causes the locking pin 2!! to be withdrawn from its locking position so as to permit the free movement again of the tubular-slide I5 along the pencil and of the cursor along both the tubular-slide and pencil. The tubular-slide may be provided with a longitudinal groove 25 in which the sprirg finger I9 rides to prevent the cursor from turning around said slide, whereby the transparent portio-n of the cursor is maintained at all times in proper relation to the scales marked on the pencil and slide respectively.

Finally, a pocket clip 21 may be secured to the cursor as shown, whereby said clip is held immovable on the device when the cursor is locked in position thereon. Thus, through a single movement of the thumb-slide the pocket-clip, cursor and tubular-slide are all three immovably xed i to the pencil.

bular-slide movable along the pencil and having a longitudinal slot registering with the scale on the pencil, a scale marked along an edge of the slot of the tubular-slide to cooperate with the scale on the pencil, and a cursor movably ernbracing the tubular-slide and having a transparent portion marked with an index line, in combination with means carried by the cursor to 3 lock the cursor tubular-slide and pencil immovably together when the device is used as a pencil.

2. The combination defined in claim 1 and further characterized by this: that the locking means carried by the cursor comprises a spring `finger having a locking lug normally held by the finger in its unlocking position, and means cooperative with the finger to move the lug into its locking position.

3. The combination dened in claim 1 and further characterized by this: that the pencil has a recess and the tubular-slide a hole adapted to register with said recess, and that the locking means carried by the cursor has a locking pin 4. The combination defined in claim 1 and further characterized by this: that the tubular-slide has a shoulder at its upper end to limit the movement of the cursor toward that end, that the pencil has a recess and the tubular-slide a hole adapted to register with said recess, and that the locking means carried by the cursor has a locking pin which registers with the hole in the tubularslide when the cursor is in its limiting position on the upper end of the tubular-slide.

5. The combination dened in claim 1 and further characterized by this: that a pocket clip is fixed to the cursor whereby the clip is held immovably to the pencil when the cursor is locked which is movable into and out of the recess and 15 to the pencil and tubular-slide.

through the hole in the tubulareslide.

ROBERT C. MAGEE. 

